Social media and TV programming have become fast friends, and, for many of us, the two are transforming how we watch television. In fact, Twitter has become a popular destination where fans can talk about their favorite TV shows in real-time. But do tweets drive consumers to tune-in to a program, or are viewers just chatting about shows they’re already watching?

The answer is both. A new independent study by Nielsen provides, for the first time, statistical evidence of a two-way causal influence between broadcast TV tune-in for a program and the Twitter conversation around that program. The study used time series analysis to determine if Twitter activity drives increased tune-in rates for broadcast TV and if broadcast TV tune-in leads to increased Twitter activity. By analyzing minute-to-minute trends in Nielsen’s live TV ratings and tweets for 221 broadcast primetime program episodes using Nielsen’s SocialGuide, the study found that live TV ratings had a meaningful impact in related tweets among 48 percent of the episodes sampled. The results also showed that the volume of tweets caused significant changes in live TV ratings among 29 percent of the episodes.

“Using time series analysis, we saw a statistically significant causal influence indicating that a spike in TV ratings can increase the volume of tweets, and, conversely, a spike in tweets can increase tune-in,” said Paul Donato, Nielsen’s chief research officer. “This rigorous, research-based approach provides our clients and the media industry with a better understanding of the interplay between Twitter and broadcast TV viewing.”

This is the first study to quantify the extent to which higher levels of tweeting may cause additional viewers to tune in to programming. The study also looked at the impact of tweets on TV ratings by program genre, and found that the influence can differ by genre. Tweets had the greatest impact on programs in the competitive reality genre, influencing ratings changes in nearly half (44%) of episodes. Episodes in the comedy (37%) and sports (28%) genres also saw significant increased tune-in from tweets, while programs in the drama genre were less affected (18%) by tweets during episodes.

The results also demonstrate what many industry observers thought to be true—that increases in TV ratings during an episode cause more people to tweet more often. This may be because there are more people available to tweet about a show, or because more compelling content drives people to tweet more often.

So what do the findings mean for the broadcast TV industry, and what’s next for Nielsen?

“Media companies and advertisers have already made investments in social media outreach as a means of engaging more directly with consumers, and we believe there are worthwhile opportunities for Nielsen to conduct additional research that can help quantify the relationship between television and social media activity,” said Donato.